Oh it's pre-menstrual whites. everyone gets them. it also 'comes out' if you're ill, stressed...it's totally normal don't worry. Shower often and if you wear short tops it might be a good idea to switch to something slightly longer. There are special herbs which you can use to get rid of it - you can ask your pharmacist for medicine/buy special padlets to prevent getting your underwear dirty. If it continues it might be that you have an infection so i suggest you go see a doctor.
And as for the sex part - again, nothing to worry about. Your boyfriend wont be like 'wtf', he's most likely to think it's cum. Go for it
